In squeeze-and-turn child-resistant closures, there are a pair of tabs on the closure that are disposed for engagement with a pair of lugs molded into a container, either on the container finish or on the shoulder of the container immediately beneath the container finish. The closure tabs are normally disposed at a position for circumferential engagement with the lugs on the container. If the closure is squeezed from opposed sides, the closure skirt is distorted sufficiently to permit the tabs to clear the lugs, and the closure to be unthreaded from the container finish. When the closure is threaded onto the container, the tabs on the closure ride over the lugs on the container, usually facilitated by angulated cam surfaces on the container lugs. The need to squeeze and distort the closure sidewall provides a child-resistant feature, whereby it is difficult for a child to remove the closure from the container and thereby obtain access to the contents of the container.
Squeeze-and-turn child-resistant closures of the described type are conventionally provided in single-wall designs and dual-wall designs. U.S. Pat. Nos. 3,917,097 and 3,941,268 illustrate single-wall designs, in which a single wall or skirt extends from the periphery of the closure base wall, with the closure internal threads being formed at the upper portion of the skirt and the lug-abutment tabs being formed at the lower periphery of the skirt. U.S. Pat. Nos. 4,117,945, 4,410,097, 5,687,863 and 5,915,576 illustrate dual-wall squeeze-and-turn closures, in which the closure internal thread is formed on the inner wall or skirt of the closure, and the tabs for abutting the container lugs are formed on the outer wall or skirt. In dual-wall closures of this character, the inner wall is spaced radially inwardly from the outer wall, and only the outer wall is distorted to remove the closure from a container. A problem with dual-wall squeeze-and-turn closures of this type is that they cannot readily be made of small size for use on small container finish sizes.
It is a general object of the present invention to provide a squeeze-and-turn child-resistant closure having a modified dual-wall construction that accommodates fabrication in all finish sizes, and that readily permits manufacture in small sizes suitable for use in conjunction with containers having reduced finish diameters. Another object of the present invention is to provide a closure of the described character in which the outer closure wall is configured to protect the force-application area for removing the closure, thereby resisting removal of the closure by application of planer force, such as by a child biting the external periphery of the closure. Yet another object of the invention is to provide a closure of the described character that requires reduced actuation force. A further object of the present invention is to provide a package that comprises a container and a squeeze-and-turn child-resistant closure of the described character, in which the lugs on the container not only resist removal of the closure in the absence of application of squeezing force to the proper areas of the closure, but also resist distortion of the outer wall of the closure. Yet another object of the invention is to provide a method of making or fabricating a squeeze-and-turn child-resistant closure of the described character.